In the present disclosure the term “work area” is used to designate a volume within which a robot tool can operate, the volume being constrained by mechanical structure of the robot. It is previously known to avoid collisions between robots by separating them enough such that their work areas do not overlap. However, such robot system has the drawback that the footprint of the same becomes large. To decrease the footprint, the robots are brought closer to each other such that their work areas do overlap. Different solutions are provided to avoid collisions in robot systems with overlapping work areas. For example, working ranges of the robots can be limited by software to be smaller than the work areas. Buffer zones within which robots are not allowed to operate can thereby be defined between the robots such that they never can collide with each other. However, in such robot system the robots' work areas are not utilized in full. Another drawback is that no operations can be performed within the buffer zones.
US20050273200A1 discloses a robot system where work areas of robots overlap. Collisions between the robots are avoided by prohibiting two robots from entering the overlapping part of their work areas simultaneously. A drawback with this solution is that the robots' capacities are not utilized in full, especially so if the overlapping areas are large.
US20140230594A1 discloses a robot system where work areas of robots overlap. Collisions between the robots are avoided by controlling the robots appropriately with a central robot controller. No details are given how this is done, but e.g. the method disclosed in US20050273200A1 could be utilized.
There remains a desire to improve the existing robot systems such that the footprints of the same are kept small while better use is made of the robots' capacities.